1. Field of the Invention
The invention relates to the type of apparatus for driving an element into the ground, or extracting an element from the ground, which is commonly termed a vibrodriver, and in which vertical vibratory or vibro-percussive forces generated by rotating eccentrics are employed to emplace or displace the element.
2. Description of the Prior Art
Vibrodriver apparatus improvements are described in U.S. Pat. Nos. 3,564,932; 3,433,311; 3,394,766; 3,391,435 and 3,368,632. The vibrodriver technique has found wide applicability in the emplacing of elements such as sheet-piles, pilings, beams, tubes, pipes, rods, or the like in the ground, as well as in the stabilization or compaction of soil as described in U.S. Pat. No. 3,621,659. Within the context of the present invention, the term vibrodriver, entailing the usage of vertical vibratory forces, will be understood to encompass and include the usage of the vibro-percussive force or mode as described in U.S. Pat. No. 3,394,766.
Vibrodrivers generate a unilinear vibration, usually vertical, for sinking, e.g. into the ground, an element such as mentioned supra, or for facilitating the extraction of such an element. Vibrodrivers include one or many pairs of identical eccentrics rotating in synchronism on opposite sides of the associated element. Heretofore, to increase the vibratory force, a vibrodriver, being constrained in configuration by the width of the element to which it was clamped, has had to be either increased in height or breadth, or both, in order to provide space for larger or more eccentrics. Such increases were undesirable but have been accepted. An increse in width has been barred because the vibrodriver would strike against or be blocked by the two elements sited on both sides of the element to be handled. This consideration applied generally to any arrangement of juxtaposed elements, e.g. a seriatim arrangement wherein the elements jointly form a straight or curved line. The same problem applies to the extraction of an element in a line of elements.